Recently, a GaN-based LED chip which emits blue light has been developed, and it is well known that this type of LED chip which emits blue light has a high luminance.
Further, recently, by utilizing the fact that such an LED chip which emits blue light has a high luminance, a surface of the LED chip is coated with light-transmitting synthetic resin containing a fluorescent material so that the light in the blue wavelength range is partially changed into yellow light by the fluorescent material contained in the coating. With this arrangement, white light with a high intensity can be generated by the color mixture.
FIG. 5 of the Patent Document 1 as a prior art shows such an LED lamp. In this LED lamp, an end of one of two lead terminals, which are made of metal, is dented to form a cup portion having an inner peripheral surface serving as a light-reflective surface. A blue LED chip is die-bonded at the inner bottom surface of the cup portion, and the LED chip is connected to the other one of the two lead terminals via a thin metal wire. The ends of the two lead terminals are covered by a transparent synthetic resin member. The blue light is changed into white light by loading, in advance, light-transmitting synthetic resin containing powder of a fluorescent material into the cup portion so that the entirety of the LED chip is embedded in the resin.
In another prior-art LED lamp, a cup portion having an inner peripheral surface flaring outward is formed at an end surface of an insulating member by denting, and a light-reflective electrode film is formed on the inner surface of the cup portion. A blue LED chip is die-bonded at the inner bottom surface of the cup portion, and light-transmitting synthetic resin containing powder of a fluorescent material is loaded into the cup portion so that the entirety of the LED chip is embedded. With this arrangement, the blue light is changed into white light.                Patent Document 1: JP-A-H11-40848        